Agronomy-3462139

Purpose: Under the background of spring drought, salinization recovery, and rigid water resource constraints in the Yellow River irrigation area of Ningxia. This study aims to investigate the effects of two different improvement measures[JC: desulfurized gypsum, ETS microbial agent, and bi-ochar composite treatment, FS: desulfurized gypsum, humic acid, and mulching composite treatment, CK: control treatment] on maize fresh biomass and the basic physicochemical prop-erties of saline-alkali soil at four irrigation levels [WI: local conventional water amount (4500 m³/hm²), W2: 10% water-saving (4050 m³/hm²), W3: 20% water-saving (3600 m³/hm²), W4: 30% water-saving (3150 m³/hm²)]. The objective is to provide a basis for water-saving irrigation in the Yellow River irrigation area of Ningxia while ensuring maize yield. Results: The results indicated that, compared to the CK treatment, both JC treatment and FS treatment reduced soil pH, with the JC treatment showing a more significant reduction in soil alkalinity than the FS treatment. Both JC and FS treatments inhibited the increase in soil EC, but the JC treatment demonstrated a signifi-cantly stronger ability to suppress EC elevation than the FS treatment. Both FS and JC treatments increased soil moisture content, indicating that they both enhanced soil water retention capacity. However, during the maize seedling stage in May, the FS treatment showed stronger water re-tention than the JC treatment; while in July (maize tasseling stage) and September (maize maturity stage), the JC treatment exhibited better water retention than the FS treatment. Under all four water conditions, both JC and FS treatments increased maize fresh biomass, but there was no significant difference between the two treatments under W1 and W2 conditions. Under W3 and W4 conditions, the JC treatment significantly outperformed the FS treatment in increasing maize fresh biomass. Specifically, under W3 conditions, the maize fresh biomass for the JC and FS treatments were 88.01 t/hm² and 85.73 t/hm², respectively, while the CK treatment under W1 conditions had a fresh biomass of 87.12 t/hm². This suggested that under the W3 condition, the JC treatment results in higher maize fresh biomass than CK under W1 conditions, whereas the FS treatment under W3 results in lower fresh biomass than CK under W1 conditions. Therefore, under the W3 irrigation condition, the JC treatment not only achieved a greater water-saving goal but also prevented yield loss due to reduced water usage.